Process for removing nitrogen compounds from hydrocarbon oil with iodine or hydrogen iodide



Jan. 3, 1956 w. l. BENTON ETAL 2,729,595

PROCESS FOR REMOVING NITROGEN COMPOUNDS FROM HYDROCARBON OIL WITH IODINEOR HYDROGEN IODIDE Filed Jan. 2, 1953 2 Sheets-Sheet 1 V-- mf DE "Z.50u/Wmv j Hmmm/PMN j! f3 Jan. 3, 1956 w. l. DENTON ET AL PROCESS FORREMOVINO NHROOEN COMPOUNDS FROM HYOROOARBON OIL WITH IOOINE OR HYOROOENIOOIOE 2 Sheets-Sheet li2 Filed Jan. 2, 1953 I/y #A7770 INVENToRs dlxafa [mian/ BY Milla, E (frn/00d TTU/@Alfy 6 w W 0l 5 w1/.nH m 4W MH Hfr, 3 F. MM w m T z MM N E c wm, A1 rv 0 0 0 0 0 0 0 0 nu 0 n 0 0 0 00au 7 5 4 3 .Z 40.. a.. b 7 ,u 5 A. M M i United States Patent-O PROCESSFOR REMOVING NITROGEN COM- POUNDS FROM HYDROCARBON OIL WITH IODINE ORHYDROGEN IODIDE Application January 2, 1953, serial No. 329,291

claims.r (ci. 19a- 39) This invention relates to a process for removingnitro gen compounds from hydrocarbon oils. More particularly, theinvention is concerned with a process for treatl ing nitrogen-containingpetroleum oils and various liquid fractions obtainable therefrom with areagent capable of selectively removing nitrogen. v,

In the rening of petroleum and fractions thereof, the presence ofnitrogen compounds has heretofore been recognized as undesirable.PetroleumI hydrocarbons generally contain varying amounts of nitrogencompounds as impurities, which are distributed in the various fractionsand products obtained from the crude hydrocarbon stocks according totheir boiling points or to theirrelative volatility in hydrocarbonmixtures. Also, the particular kind and amounts of nitrogen compoundspresent in a petroleum hydrocarbon vary with the previous manufacturingand processing operations to which said petroleum hydrocarbon has beensubjected. The presence of nitrogen compounds in hydrocarbon oils isobjectionable since they tend to destroy the activity of hydrocarbonconversion catalysts with which the oil may be brought into contactduring various processing operations. Thus, in catalytic cracking of ahydrocarbon oil containing an appreciable amount of nitrogen compounds,the catalyst prematurely loses activity due to the poisoning effects ofthe nitrogen compounds. i

It is a major object of the present invention to provide a method forremoving objectionable nitrogen compounds from hydrocarbon oilscontaining the same. A further object is the provision of a process foreffecting selective denitrifying of hydrocarbon oils wherein thenitrogen content thereof is effectively reduced without adverselyinuencing the yield and quality of the resulting denitrized product. Astill further object is the development ofv a commercially attractiveprocess for removing nitrogen compounds from hydrocarbonoils containingthe same which is capable of continuous operation. p

These and other objects which will be `apparent to `those skilled in theart are achieved in accordance with the present invention. Broadly, theprocess described herein involves treating hydrocarbon oils` containingnitrogen compounds with hydrogen iodide, iodine, or a hydrogeniodide-iodine mixture at a moderate temperature below that at whichappreciable cracking of the hydrocarbon charge stock to lighter materialis encountered.

It has been discovered, in accordance with the present invention, thatiodine, hydrogen iodide, and mixtures thereof, under particularlydefined reaction conditions hereinafter set forth, provide a highlyeliicient and selective means for effecting removal of nitrogen fromhydrocarbon oils containing thesarne. lt is contemplated thathydrocarbon oils which contain nitrogen compounds may generally betreated in accordance with the instant process. Thus, petroleum crudes,gas oils, and reduced crudes containing nitrogen have been effectivelytreated with resulting denitriiication thereof. The process is mosteffective in treatment of gas oils which contain organic nitrogencompounds.

The process of the invention involves contacting a nitrogen-containinghydrocarbon stock with hydrogen iodide, iodine, or a hydrogeniodide-iodine mixture under hereinafter dened reaction conditions. Theproducts resulting from the treatment comprise gases, denitrized liquidhydrocarbon product, and a tarry precipitate. The denitrized liquidhydrocarbon product normally contains a small amount of Hl or iodinewhich can be removed by water-washing. A caustic wash is desirable toinsure complete removal of HI or iodine from the hydrocarbon. Asubstantial proportion of HI charged may be recovered by extracting thetarry precipitate with water, and the extract may be recycled forfurther use in denitrifying. The remaining iodine, elemental and/o1combined, may be recovered from the water-washed tarry precipitate byburning at an elevated temperature. The iodine so recovered may likewisebe employed in effecting further denitrication. The gaseous reactionproduct contains a substantial proportion of light hydrocarbons and may,after scrubbing with water to recover any HI, be conducted to storagefor use as a fuel gas.

Figure l of the attached drawing illustrates in schematic form asuitable system for carrying out the process abovedescribed, whereinaqueous hydrogen iodide solution is used as the treating reagent.Referring more particularly to Figure l, the hydrocarbon stockundergoing treatrnent enters reactor 10 through conduit 11. Aqueous HIsolution is conducted to reactor 10 from storage tank 12 through conduit13. The contents of the reactor are then heated under the desiredconditions of temperature, pressure, and time hereinafter specied. Theproducts resulting from this treatment consist of a mixture of hydrogenand light hydrocarbon gases, denitrized liquid hydrocarbon stock, and atarry precipitate. After the aforementioned heat treatment, the gaseousproducts are removed from the reactor through outlet pipe 14, the rateof iiow being controlled by valve 15. After the gaseous products havebeen withdrawn, the liquid content of the reactor is removed throughoutlet conduit 16 upon opening valve 17 and passes into settling tank18. The liquid product consists of an aqueous layer and an overlying oillayer. The oil layer is withdrawn from the settling tank through outletconduit 19 and passes into a wash tank 20, wherein it is washed free ofHI with water introduced through conduit 21. The washed denitrized oilproduct is withdrawn through outlet conduit 22 and the wash watercontaining soluble matter is withdrawn through outlet conduit 23.

The tarry precipitate is collected on an inclined screen 24 in reactor10 and is withdrawn from the reactor through a trap door 25 in thereactor wall. The tarry precipitate passes from the reactor through saidoutlet into a wash vessel 26. Water is led into vessel 26 throughconduit 27 and the water containing extracted HI is withdrawn throughoutlet 28 and forced through conduit 29 by means of a pump, not shown,to storage tank 12. The aqueous layer in settling tank 18, containingdissolved HI, is withdrawn from the bottom of the tank through outletconduit 30 and is recycled along with the aqueous tar extract throughconduit 29 to storage tank 12. The tarry precipitate in vessel 26, afteraqueous extraction thereof, is withdrawn upon opening valve 31 andpasses through conduit 32 into a furnace 33. Air or other suitablecombustion supporting gas is led. into the furnace through conduit 34and iodine is removed from the tar by burning at an elevatedtemperature. Released iodine fumes pass through outlet conduit 35 andthrough a series of scrubbers 36 containing water in which iodine isprecipitated and collected on screens 37. The scrubbers areinterconnected by pipes 38 and the water may be withdrawn therefromthrough outlet conduit 39. The iodine collected on the trays andscrubbers 36 is removed at intervals and may be employed in preparingaqueous HI solution such as by bubbling a stream rich in H28 through anaqueous suspension of iodine for further denitrifying activity, or theiodine itself may be used for accomplishing denitrifying upon bringingthe same into contact with the hydrocarbon stock under the reactionconditions of the invention.

The method of the invention must be carried out under specific operatingconditions in order to effect removal of the nitrogen compounds withoutdetrimentally affecting the yield of desired denitrized product. Thus,it has been found that the temperature. of the instant process must bemaintained within the approximate range of 200 F. to 850 F. Below about200 F., substantially no denitrifying occurs while 4at temperatures inexcess of 850 F., appreciable cracking of the hydrocarbon stock takesplace, resulting in distinctly lower liquid recovery and higher gas-makewithv little additional denitrifying.

Figure 2 of the attached drawing shows the effect of temperature on theextent of nitrogen removal and the volume yield of treated liquidproduct on contacting a hydrocarbon charge of light gas oil initiallycontaining 0.26 per cent nitrogen with an aqueous solution of HI underreaction conditions where the reaction time was 2 hours, anapproximately 50 per cent aqueous HI solution was employed, and theratio of I/N, i. e., the ratio of gram atoms of iodine to gram atoms ofnitrogen contained in the charge Vstock was 5.8. Under theaforementioned contacting conditions, the effective reaction temperaturerange for accomplishing denitrifying was between about v 200 F. andabout 850 F. It will be noted from an examination of Figure 2 that theextent of nitrogen removal rapidly increased with a rise in temperatureuntil about 750 F. was reached, with a slight reduction in yield ofdesired product. ln the range of 750 F. to 850 F., the amount ofdenitrifying increased but at a much lower rate and with a rapid declinein product yield. Above about 850or F., no further substantialdenitrifying was accomplished and the yield of liquid product,A due tocracking, greatly decreased. The preferredl temperature range foroperation of the instant process isaccordingly between about 650"Y F.and about 750 F.

Figure 3 of the drawing shows the effectv of reaction time on the extentof nitrogen removal using the above identified stock, a temperature of700 F., a 50.5 per cent aqueous Hf'solution and an I/ N ratio of 5.8.From an examination of this figure, it will be seen that an increase inreaction time increased the extent of nitrogen pounds was accomplished.While excessively long reaction times should beV avoided to avoiddegradation of the stock, it is contemplated that a reaction time up toabout l hours may be employed, particularly with the use of lowertemperatures. While some denitrifying is accomplished using a residencetime as low as .0l hour, in the preferred temperature range the optimumdenitrifying is obtained, as will be noted from Figure 3, at between'about 2 and aboutv 7 hours.

Figure 4 of the attached drawing shows the effect of l/N ratio on theextent of denitrifying using the same stock and reaction conditions asreported for Figure 2, with the exception that a reaction time of about2 hours and a varying I/N ratio was employed.v The l/ N ratio representsthe ratio of gram atoms of iodine present in ,the HI or iodine reagentused to the gram atoms of nitrogen present in the hydrocarbon stockundergoing treatment.

Upon examination of this figure, it will be seen that more denitrifyingoccurred with. higher I/ N ratios but with less v efficient use ofthereagent. Thus, it will be noted that an increase in the l/ N ratioincreased the extent of nitrogen removal rapidly up to an I/N ratio ofabout 1. Thereafter, with increasing I/ N ratios, the extent ofdenitrifying proceeded but at a much slower rate. Ratios of 0.005 to 6are operable. A ratio of less than about 0.005 reduces the totalnitrogen to a minor extent while little additional denitrifying isobtained by increasing the ratio above about 6. Generally, an I/N ratioof between about 0.03 and about 5y is preferred for use in the presentprocess.

Figure 5 of the attached drawing shows the effect of concentration of HIin water on denitrifying using a fixed I/ N ratio of 5.8, a reactiontime of 2 hours, and a temperature of 700 F., on the above-identinedhydrocarbon stock. From an examination of this figure, it will be notedthat the degree. of denitrifying varied directly with the concentrationof HI in water. Thus, approximately twice as much denitrifying wasobtained with a 50 per cent HI solution as compared with a 25 per centHI solution in water. Without being limited by any theory, it is believed that this phenomena is due to the lower concentrationof HI in thehydrocarbony phase when more water is present, since the HI is moresoluble in water than in oil.

The agent employed herein in effecting denitrifying may be eitheriodine, hydrogen iodide, or a mixture of iodine and hydrogen iodide. Thereagent may be employed either in dry form or in the form of a solutionin a suitable solvent. Thus, HI is conveniently employed in the form ofan aqueous solution but also may be used in a solution of a lowmolecular weight alcohol or other solvent. Likewise, iodine may be usedin the form of a solution in an alcohol or other suitable solvent. Asv ageneral rule, iodine will dentrize more effectively under givenconditions than HI but at a somewhat lower yield level. The dentrifyingactivity of iodine and the yield level of aqueous HI may be obtained byemploying a concentrated solution of iodine inV HI, for example, asolution of 40 to 60 wt. per cent iodine in 55 per cent aqueous HI. Thehydrocarbon stock may also be denitrized with the tarry precipitatewhich is formed during theA reaction and which contains elementaliodine. lt has been found that this tar possesses the ability todenitrify hydrocarbon stock, and reuse of the tar containing iodineappreciably decreases the amount of fresh make-up iodine or hydrogeniodide required. With the use of aqueous hydrogen iodide as the treatingreagent, it Vwas found that the presence of a small amount of redphosphorus promoted the reaction so that a much lower I/-N ratio maybeemployed for a predetermined extent of d'enitrifying as compared withthe I/N' ratio used in the absence of red phosphorus. The presence ofhydrogen in the reaction mixture was found to increase liquid recoveryand to increase the extent of denitrifying. Accordingly, the'presence ofhydrogen in an amount sufficient to maintain the hydrocarbon oil inliquid phase and generally between about 100 and about 3000 p. s. i. g.pressure effects a decrease in the amount of HI or iodine required.

The denitrifying obtained with the use of iodine, hydrogenV iodide, ormixtures thereof in accordance with the present process isy unique incomparison with the treatment of nitrogen-containing hydrocarbon stockswith other halogens or hydrogen halides. Thus, in comparable runs,aqueous HBr denitrified hydrocarbon stock 5 3 per cent and aqueous HC1l50 per cent under conditions at which aqueous HI rdenitrilied theidentical stock per cent. The process described herein affords a methodin which the HI or iodine combines selectively with nitrogen compoundswith resultant high yields of liquid product. In contrast to the presentprocess, treatment of nitrogen-containing stocks with HF, for example,throws out asphaltic materials which are higher in nitrogen content thanthe remainder of the stock and thus denitries only in proportion to theamount of asphalt and nitrogen content of the asphalt.V Accordingly,with HF, poor yields and poor selectivity result while treatment withhydrogen iodide or iodine 'in accordance with the instant processaffordshigh yields and good selectivity.

ample 1. The treating conditions and results are set forth in Table Ibelow:

Table I Values For Reaction Conditions Liquid Hydrocarbon Product oLiqJuid Hydro- Aqueous oar on product s if Ex Layrir 4we ample 55% HI BVOL Wt. Sgds VOL Percent Stock, Temp., Time, ggg Cc Specific mfg percentpercent Grams percent tlizll cc. Ratio F. Hrs. p. s i g Gravity Na Aro-Nitro- Recov- Nm@ Grams IIN matics gen ery gen No. 2 Fuel Oil (I, B. P.

344 F., 50% 558 F., End Point 658 F.) 2 200 22 18. 6 700 2 400 184 0.8922 13 40 0.03 28 92.0 25 California Crude Oil (I. B. P. 170 F., 50%695 F.Craclti11g) 3 200 36 2. 4 700 2 950 178 0. 8065 12 0.18 56 89. 063 California Residuum (I. v

B. P. 515 F., 50% 940 F., 75% l1100 F.) 4 200 8l 3. 2 700 2 700 195 1.0021 0. 69 8l 97. 5 12 The following examples will serve to illustratethe process of the invention without limiting the same:

EXAMPLE 1 A 1/z-liter stainless steel rocking type bomb was charged with177 grams (200 cc.) of a light gas oil having a nitrogen content of 0.26per cent by weight and a boil'- ing range of 145 F. to 652 F. An aqueoussolution of 55 per cent by weight of hydrogen iodide was added It is tobe noted from the above examples that the process of this invention isbroadly applicable in denitrifying a variety of petroleum stocks withhigh volume per cent recovery.

The elect of the presence of hydrogen in the reaction mixture isillustrated by the following comparative examples. The procedureemployed was substantially that described in Example 1. ,The treatingconditions and results are set forth in Table II below:

Table II React-ion Conditions Liquid Hydrocarbon Product Values ForLiquid H y d r o c a r b o n Aqueous Product Aqueous HI Layer ExampleGas Bm Vol. Wt. and

ou Ratio, Temp., Time, Pressure cc Specific mine Percent Percent Solids,V01 Percent Concn., I/N F. Hrs. p. s. i. g. Gravity No Aro- Nitro- GramsPerce'nt Reducc- Wt, Grams matics gen Recover in Percent Y Nitrogen tothe bomb in the amount of 41 grams. The head The foregoing examples werecarried out under sub- Mole percent Hydrogen 36.4 Methane 34.8 Czs 14.4Cas 6.5 Cis 2.5 C5s 0.9

The head was removed from the bomb and 167 grams of liquid productconsisting of 6 cc. of aqueous layer and 184 cc. of oil layer weredecanted. The oil layer was extracted three times with 250 cc. portionsof water to remove iodide therefrom. The ranate (182 cc.), after drying,was found to have a nitrogen content of 0.04 per cent. Finally, 49 gramsof wet, tarry sludge were removed from the bottom of the bomb. Therecovery of liquid hydrocarbon product was accordingly 91 per cent andthe reduction in nitrogen content was 85 per cent.

The following examples were carried out on various petroleum stocksfollowing the general procedure of Ex- EXAMPLE 7 Two hundred cc. of alight gas oil having the properties set forth in Example 1 werecontacted with 1 gram of an aqueous solution of 55 per cent by weighthydrogen iodide and 2 grams of red phosphorus in a rocking type bomb.The bomb was closed and the temperature raised to approximately 700 F.and maintained at this temperature for about 2 hours. The pressureattained was less than p. s. i. g. At the end ofthe reaction time, theheat was turned oif and the bomb was allowed to cool to roomtemperature. A liquid hydrocarbon product in the amount of 187 grams wasobtained, having a nitrogen content of 0.11 per cent. The reduction innitrogen was accordingly 58 per cent by Weight and the volume per centrecovery of liquid hydrocarbon product was 93.5 per cent. A comparablerun in the absence of added red phosphorus, employing the equivalentsmall I/ N ratio of 0.03. as will be evident from an examination ofFigure 4, affords only about 8 per cent removal of nitrogen.

e 8 The effect of iodine and mixture of H1 and iodine on EXAMPLE. 16 theextent of nitrogen removal of the gas oil defined inV Example 1 is shownin the examples set forth in Table Two hundred cc. of a gas oil havingthe properties III below: defined in Example 1 were contacted with 47grams of Table III l Values for liquid Reaction conditions Liquidhydrocarbon product hydrocarbon product Aqueous l A HI layr Examp equeous an G Bw Voi. Wi. sonas, voi. lgfft Ols .Added Ratio Temp., Time,Pressure cc Speelde mme percent percent grams percent t. n fn Ceneri..1g, g. I/N F. lirs. p. s. i. g. gravity No aro- Nitrorecov- Igitm; ccwt. per- Grams matics gen ery en cent g 200 41 0 5. 8 705 2 950 1820.8649 11 40 0.04 59v v 11.0 85 200 55 10 17 5.8 695 2 1, 350 180 0.859714 41 0.02 53 00;() 02 200 19.5 5.0 702 2 300 170 0.8654 12 (i3l 0.02 388.5.0 92 200 55 2. 5 4. 2 1. 4 700 2 100 180 0. 8745 18. 4 37 0. 11 1500. 0 58 200 1' (3) "0. 14 700 2 100 186 0. 8762 14.9 39 0. 16 21 03. 030 55 1 (4) l 0. 14 700 2 100 184 0. 8745 31. 7 20 0.16 26 92.0 39

1 Ratio (HH-D/N.

2 Iodine in tar excluded. 2 15 g. tar from Ex. 11.

4 21 g. tar from Ex. 12.

It will be noted from the comparative results of Examples 8 to i3 thatthe denitrifying activity of iodine under given conditions is greaterthan aqueous. HI but that a somewhat lower volume recovery is obtained.It is further to be noted from Examples 9 and 11 that the denitrifyingactivity of iodine and the yield level of aqueons HI may be obtained byusing a concentrated solution of iodine in aqueous Hl. Thus, in Example9, a solution of 17 grams or" iodine in l0 grams of 55 per cent aqueousHl effected 92 per cent reduction in nitrogen at a 90 volume per centyield level while, under the same conditions, treatment with iodinealone in Example 10 and treatment with 55 per cent aqueous HI alone inExample 8 gave 92 and 85 per cent reduction in nitrogen and 85 and 91volume per cent yields, respectively. In Examples 12 and 13, the reagentused consisted of a small amount of aqueous HI in admixture with thetarry precipitate obtained from a previous run. As will be noted, theuse of tarry precipitate aorded a substantial reduction in nitrogencontent of the hydrocarbon charge of deiiitrifying with iodine and H1 inaccordance with l 48 per cent by weight aqueous HI. The l/N ratio was5.8. The mixture of HI and oil were heated to 650 F. in a closed vesselfor 2 hours at a pressure of 1000 p. s. i. g. At the end of this time,gaseous products were vented and 190 cc. of a liquid hydrocarbon producthave ing a nitrogen content of 0.10 per cent by weight was obtained. Thevolume recovered was, accordingly, 95 per cent and the per centreduction in nitrogen was 62 per cent.

The liquid product obtained in this example consisted of an aqueouslayer which contained HI and a hydrocarbon layer. In addition to thegaseousland liquid products, a tarry precipitate was obtained whichcontained iodine and absorbed HI.. The terry precipitate was extractedwith Water and the resulting extract combined with the aqueous layer.The resulting combined mixture *tf-:as found to contain 38 per cent byweight of the HI charged. The tarry precipitate, after extraction withwater, contained 56 per cent by weight of the HI charged. This tai' washeated in a current of air to recover iodine. The eluent gas wasscrubbed in 3 successive water towers to precipitate iodine.Eighty-three per cent of the iodine in the tar was recovered at amaximum temperature of 650 F.

. '0 the present process is much greater than corresponding Fmi?, theabove example t W'll be noted that a large treament with other hydmgenhalides Comparative proportion of the treating reagent used can belrecovered. data showing the treatment or the gas oil having the Suchfecoveredhydrogen Odlfle and/ 01' lofme may be properties defined inExample l with Hl, HBr, and HC1 used fOl' effecting furtherdenltl'lfymg- Nitrogen Comiinder conditions wherein the ratio 'ofhalogen to nitrogen '"5 pounds contained in the tarry precipitate may bereis fixed are sct forth in Table IV below: covered if desired byextracting the precipitate with an Table 1V Reaction Conditions LiquidHydrocarbon Product Values For *a Liquid Hydrol ue carbon'ProductAqueous Hydrogen Halide ougla i Example I V01. Wi.. er and gs Temp.,Time, Pressure, cc Specific Percent Percent Solids, Vol. ce' Genen., F.Hrs. p.s.-i.g. gravity No Aro- Nitro Grams Percent da .n Wt. GramsRatio, Halogen/u matics gen Rec-ow Nitr Percent cry 200 HI 4i I/ N 5.8705 2 950 182 0.8649 11 40 0.04 50 91.0 as 20o 48 HBR y20.6 Biz/N 5.8700 2 c25 ist 0.8810 0.12 40 92.0 53 200 3s HOL 17 CLIN 5.a 700 2 550183 0.8762 12.0 37 0.13 24 01.5 50

rom the foregoing data, it will be noted, under the aromatic hydrocarbonsolvent, such as benzene, toluene, comparable conditions shown, aqueous.HBr denitrized xylene, and the like. the stock 53 per cent and aqueousHC1, 50 per cent, It is to be understood that the above description iswhile the extent of nitrogen removal obtained with aquemerelyillustrative of the preferred embodiments of the ous HI was per cent. 75invention, of which many variations may be made within 9 the scope ofthe following claims by those skilled in the art without departing fromthe spirit thereof.

We claim:

1. A process for denitrifying a nitrogen-containing hydrocarbon oil,which` comprises contacting said oil at a temperature between about 650F. and about 750 F. with a reagent selected from the group consisting ofiodine, hydrogen iodide, and an iodine-hydrogen iodide mixture, andpresent in such amount that the ratio of gram atoms of iodine in saidreagent to the gram atoms of nitrogen contained in said oil is at leastabout 0.005.

2. A process for denitrifying a nitrogen-containing hydrocarbon oil,which comprises contacting said oil with a reagent selected from thegroup consisting of iodine, hydrogen iodide, and iodine-hydrogen iodidemixtures at a temperature between about 650 P. and about 750 F. for aperiod of between about 0.01 and about 10 hours, the ratio of gram atomsof iodine present in said reagent to the gram atoms of nitrogencontained in said oil being between about 0.005 and about 6.

3. A process for denitrifying a nitrogen-containing hydrocarbon oil,which comprises contacting said oil with a reagent selected from thegroup consisting of iodine, hydrogen iodide, and iodine-hydrogen iodidemixtures at a temperature between about 650 F. and 750 F. for a periodof between about 2 and about 7 hours, the ratio of gram atoms of iodinepresent in said reagent to the gram atoms of nitrogen contained in saidoil being between about 0.005 and about 6.

4. A process for denitrifying a nitrogen-containing hydrocarbon oil,which comprises contacting said oil at a temperature between about 650F. and about 750 F. with a solution of iodine and hydrogen iodide, theratio of total gram atoms of iodine to gram atoms of nitrogen containedin said oil being at least about 0.005.

5. A process for denitrifying nitrogen-containing hydrocarbon oil, whichcomprises contacting said'oil with a reagent selected from the groupconsisting of iodine, hydrogen iodide, and iodine-hydrogen iodidemixtures in the presence of between about 100 and about 3000 p. s. i. g.pressure of hydrogen at a temperature between about 650 F. and about 750F., the ratio of gram atoms of iodine present in said reagent to thegram atoms of nitrogen contained in said oil being at least about 0.005.

6. A process for denitrifying a nitrogen-containing hydrocarbon oil,which comprises contacting said oil with a reagent selected from thegroup consisting of iodine, hydrogen iodide, and iodine-hydrogen iodidemixtures in the presence of hydrogen at a temperature between about 650F. and about 750 F., the ratio of gram atoms of iodine present in saidreagent to the gram atoms of nitrogen contained in said oil being atleast about 0.005.

7. A process for denitrifying a nitrogen-containing hydrocarbon oil,which comprises contacting said oil with hydrogen iodide in the presenceof red phosphorus at a temperature between about 650 F. and about 750F., the ratio of gram atoms of iodine present in said hydrogen iodide tothe gram atoms of nitrogen contained in said oil being at least about0.005.

8. A continuous process for denitrifying a nitrogencontaininghydrocarbon oil, which comprises contacting said oil at a temperaturebetween about 650 F. and about 750 F. with a reagent selected from thegroup consisting of iodine, hydrogen iodide, and iodine-hydrogen iodidemixtures, the ratio of gram atoms of iodine present in said reagent tothe gram atoms of nitrogen contained in said oil being at least about0.005, separating the resulting denitrized oil from a residualiodinecontaining tarry precipitate and recycling said tarry precipitatefor use as the aforesaid reagent.

9. A continuous process for denitrifying a nitrogencontaininghydrocarbon oil, which comprises contacting said oil at a temperaturebetween about 650 F. and about 750 F. with aqueous hydrogen iodidesolution, the ratio ot' gram atoms of iodine present in said solution tothe gram atoms of nitrogen contained in said oil being at least about0.005, separating the resulting liquid product consisting of adenitrized oil layer and an aqueous layer containing dissolved hydrogeniodide from a residual tarry precipitate, contacting said precipitatewith Water to remove an aqueous extract of hydrogen iodide therefrom,separating the aforementioned denitrized oil layer and aqueous layer,combining the latter with said aqueous extract and recycling theresulting combined aqueous hydrogen iodide to contact with a charge ofthe original oil.

10. A continuous process for denitrifying a nitrogencontaininghydrocarbon oil, which comprises contacting said oil at a temperaturebetween about 650 F. and about 750 F. with aqueous hydrogen iodidesolution, the ratio of gram atoms of iodine present in said solution tothe gram atoms of nitrogen contained in said oil being at least about0.005, separating the resulting liquid product consisting of adenitrized oil layer and an aqueous layer containing dissolved hydrogeniodide from a residual tarry precipitate, washing said precipitate withwater to remove an aqueous extract of hydrogen iodide therefrom, heatingthe washed precipitate to ignition, recovering iodine vapors evolvedtherefrom, separating the aforementioned denitrized oil layer andaqueous layer, combining the latter with said aqueous extract andrecycling the resulting combined aqueous hydrogen iodide to contact witha charge of the original oil.

References Cited in the file of this patent UNITED STATES PATENTS 74,756Flowers et al. Peb. 25, 1868 1,843,516 Oberle Feb. 2, 1932 2,174,810 VonFuchs et al Oct. 3, 1939

1. A PROCESS FOR DENITRIFYING A NITROGEN-CONTAINING HYDROCARBON OIL,WHICH COMPRISES CONTACTING SAID OIL AT A TEMPERATURE BETWEEN ABOUT 650*F. AND ABOUT 750* F. WITH A REAGENT SELECTED FROM THE GOUP CONSISTING OFIODINE, HYDROGEN IODIDE, AND AN IODINE-HYDROGEN IODIDE